TRUNCATETABLEHANG(二)
keys | relfkeys | relrefs | relhasoids | relhaspkey |
relhasrules | relhassubclass | relfrozenxid | relacl | reloptions
------------------------+--------------+----------+----------+-------+-------------+---------------+----------+-----------+---------------+---------------+------------
---+---------------+-------------+-------------+---------+------------+----------+-----------+-------------+----------+----------+---------+------------+------------+-
------------+----------------+--------------+--------+------------
cannottruncatetable | 17021 | 11051471 | 17010 | 0 | 23496358 | 0 | 16 | 0 | 11052150 | 0 |
0 | 0 | f | f | r | h | 22 | 0 | 0 | 0 | 0 | 0 | f | f |
f | f | 1558793687 | |
(1 row)
gtlions=# select pg_size_pretty(pg_relation_size('gtlions.cannottruncatetable'));
pg_size_pretty
----------------
512 kB
(1 row)
gtlions=# select pg_backend_pid();
pg_backend_pid
----------------
14027
(1 row)
gtlions=# select now();
now
-------------------------------
2014-10-15 16:52:25.112906+08
(1 row)
gtlions=# truncate table gtlions.cannottruncatetable;
Cancel request sent
ERROR: canceling statement due to user request
gtlions=# select now();
now
-------------------------------
2014-10-15 16:53:39.877717+08
(1 row)
###################On the session 2:
During the session 1 running, open new session 2, check the session 1
gtlions=# select procpid,sess_id,usename,current_query,waiting,age(now(),query_start) from pg_stat_activity where procpid=14027;
procpid | sess_id | usename | current_query | waiting | age
---------+-----------+---------+-----------------------------------------------+---------+-----------------
14027 | 113747736 | gpadmin | truncate table gtlions.cannottruncatetable; | f | 00:00:49.671096
(1 row)
gtlions=# select * from pg_locks where pid=14027;
locktype | database | relation | page | tuple | transactionid | classid | objid | objsubid | transaction | pid | mode | granted | mppsessionid |
mppiswriter | gp_segment_id
---------------+----------+----------+------+-------+---------------+---------+-------+----------+-------------+-------+---------------------+---------+--------------+
-------------+---------------
relation | 17020 | 11052151 | | | | | | | 1658824590 | 14027 | AccessExclusiveLock | t | 113747736 |
t | -1
relation | 17020 | 11051470 | | | | | | | 1658824590 | 14027 | ShareLock | t | 113747736 |
t | -1
relation | 17020 | 11051470 | | | | | | | 1658824590 | 14027 | AccessExclusiveLock | t | 113747736 |
t | -1
relation | 17020 | 11052150 | | | | | | | 1658824590 | 14027 | ShareLock | t | 113747736 |
t | -1
relation | 17020 | 11052150 | | | | | | | 1658824590 | 14027 | AccessExclusiveLock | t | 113747736 |
t | -1
transactionid | | | | | 1658824590 | | | | 1658824590 | 14027 | ExclusiveLock | t | 113747736 |
t | -1
(6 rows)
gtlions=# select procpid,sess_id,usename,current_query,waiting,age(now(),query_start) from pg_stat_activity where procpid=14027;
procpid | sess_id | usename | current_query | waiting | age
---------+-----------+---------+-----------------------------------------------+---------+-----------------
14027 | 113747736 | gpadmin | truncate table gtlions.cannottruncatetable; | f | 00:01:03.655322
(1 row)
gtlions=# select * from pg_locks where pid=14027;
locktype | database | relatio
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